In automobile assembly line operations, there may sometimes occur a trouble such that the coated surface of a vehicle body becomes damaged as a tool or a part comes in contact with the body. Techniques for preventing such a trouble are known as described in, for example, Japanese Laid-Open Utility Model Application No. 60-85220. In this known technique, a synthetic resin-made working protection cover for damage prevention is used to cover various automotive parts, such as fenders, bumpers, doors, hoods, side panels, side sills, and trunk lids, for protection from possible damages. Such a working protection cover includes a cover body, and a locking edge formed along the outer peripheral edge of the cover body which is to be brought in locking engagement with an outer perpheral portion of an automotive fender, bumper or the like to enable the same to be covered. However, such a cover involves a problem that it may easily slip off the surface upon a mere contact of an operator with the cover because it is comprised of a soft synthetic resin film.
A cover of this type is constructed of a thermoplastic PP (polypropylene) sheet with a PE (polyethylene) foam plastic sheet bonded to the inner peripheral surface of the PP sheet. This working protection cover is manufactured in such a way that a sheet base is first fabricated by bonding a PE foam plastic sheet to the back of a PP sheet and then the sheet base is heated and pressed by a forming die so as to form a cover of a particular configuration. Unfortunately, such a conventional type working protection cover has disadvantages arising from the difference in shrinkage between the PP sheet and the PE foam plastic sheet, the shrinkage factor of the former sheet being smaller and that of the latter being larger. That is, because of such difference in shrinkage, the cover tends to curl in course of time, thus becoming unusable or losing much of its performance characteristics. Further, the PE foam plastic sheet is likely to become damaged and lacks durability.